Generally, a microwave apparatus or a RF wireless apparatus needs a microwave generator to generate a microwave signal.
The microwave generator is usually equipped with a power supply. The power supply is used for converting an input voltage and an input current into required output electric power. The output electric power is provided to the corresponding circuitry of the microwave generator. Consequently, the microwave generator can normally generate the microwave signal. For achieving the power factor correction function, the power supply of the microwave generator has a two-stage configuration. That is, the power supply of the microwave generator comprises a power factor correction circuit and a power converter. The power factor correction circuit is used for causing the input current received by the power supply to follow a sinusoidal waveform in phase with the input voltage so as to correct the power factor of the power supply and reduce the harmonics. The power converter is used for converting the electric power outputted from the power factor correction circuit into an output voltage and output current.
By the power factor correction circuit, the input current and the input voltage are in phase. However, since the power factor correction circuit is costly, the use of the power factor correction circuit increases the fabricating cost and the volume of the microwave generator.
Therefore, there is a need of providing a microwave generator with a power factor correction function and a control method thereof in order to overcome the above drawbacks.